Dried powder of corn stalk as a potential biosorbent for the removal of iodate from aqueous solution

Removal of IO₃^- from environmental samples with low-cost methods and materials is very useful approach for especially large-scale applications. Corn stalk is highly abundant agriculture residual, which is employed as useful biosorbent in many studies. In the present work, dried powder of corn stalk is applied for the removal of IO₃^- under various conditions. The results indicate that the K_d is 49.73 ml g^-1 under general conditions (m/V = 8 g L^-1, t = 5 day, equilibrium pH = 7 ± 0.3, T = 298 K and C₀ = 15 mg L^-1). The sorption kinetics follows the pseudo-second-order equation, and the isotherm is well described by the Langmuir model. The sorption reaction was non-spontaneous and endothermic. Hydroxyl and carbonyl groups of the corn stalk contribute to IO₃^- sorption by ion-exchange, electrostatic attraction and redox reactions. Spectroscopic analyses and the effect of equilibrium pH prove that corn stalk was not only removed IO₃^- from aqueous solution but also reduced IO₃^- into I₂ and I^-. These results demonstrate that corn stalk is a promising biosorbent for the environmental remediation of radioactive iodine pollution.